1. Field of the Invention
The present invention relates to a magnetic recording apparatus and a magnetic recording and reproducing apparatus, and in particular, a magnetic recording apparatus and a magnetic recording and reproducing apparatus in which information is recorded on the basis of arrangement of a magnetic material and in which a pattern area in which the magnetic material arrangement cannot be changed even by a read and write head is recorded on a magnetic recording medium, the magnetic recording apparatus and magnetic recording and reproducing apparatus being able to execute magnetic additional recording on the magnetic material in the non-rewritable area.
2. Description of the Related Art
Owing to the need to meet requirements for an increase in the storage capacity of magnetic recording apparatuses (also hereinafter referred to as magnetic disk apparatuses or hard disk apparatuses), demands have been made for an increase in the recording density of magnetic recording medium. However, an increase in recording density has disadvantageously caused magnetic information recorded by a read and write head moving relatively on a recording medium to affect recording in an adjacent track. This problem can be avoided by physically separating the parts of the magnetic material in adjacent tracks from one another.
For example, JPA 10-255407 (KOKAI) proposes a magnetic recording medium in which servo or ROM information is non-rewritably recorded on the basis of the presence of a magnetic material by patterning the magnetic material on the magnetic recording medium.
For example, JPA 10-255407 (KOKAI) discloses a scheme of enabling servo or ROM information to be recorded on the basis of the presence of a magnetic material by patterning the magnetic material on the magnetic recording medium.
In a recording portion, ROM information is recorded by patterning a magnetic material. In general, if information is newly recorded in an area in which the ROM information has been recorded, magnetic segments and nonmagnetic segments are inconsecutively arranged in the area; magnetic information can be recorded in the magnetic segments but not in the nonmagnetic segments. Consequently, when a write head provided in a recording and reproducing apparatus is used to overwrite the recording portion in which ROM information has already been written, information is not recorded in the nonmagnetic segments present in the recording portion. Thus, the overwritten information cannot be reproduced. As a result, with a magnetic recording medium with ROM information, an additionally recordable capacity is equal to the recording capacity of the entire medium minus the amount corresponding to the recording portion in which the ROM information has been recorded. This reduces the recording capacity of the entire recording medium. However, demands have been made to provide a sufficient additionally recordable capacity for a magnetic recording medium with a ROM information recording portion to minimize a decrease in additionally recordable capacity.